| Abstract: | Contrasting decrease and increase trends of sea surface temperature (SST) have been documented in the western Subarctic (WSA) and the rest of the Northwest Pacific (NWP) from 1958 to 2017, respectively. Consequently, more (less) total carbon dioxide (TCO2) due to ocean cooling (warming) is transported to the surface, which leads to increase (decrease) of oceanic surface partial pressure of carbon dioxide (pCO2). With the combined influence of the rising atmospheric carbon dioxide (CO2) level and changing ocean conditions, a prominent increase in oceanic surface pCO2 occurred with different rates of increase in summer and winter in the NWP. The oceanic surface pCO2 is mainly controlled by the variation of TCO2 at the interdecadal timescale and by SST at the seasonal timescale. Our results also indicate that increasing SST tends to strengthen the capability of ocean in absorbing anthropogenic CO2 in the NWP, while ocean’s uptaking ability is weakened in the cooling area of the WSA. |
